No abstract

Growth hormone deficiency (GHD) and central precocious puberty (CPP) have each, individually, been described in patients with Klinefelter syndrome. However, the combination of GHD, CPP, and Klinefelter syndrome has never been reported. We described a Klinefelter syndrome patient who developed GHD at age 2 10/12 years and CPP at 8 6/12 years. Despite CPP, GnRH agonist therapy was not initiated because of his excellent predicted adult height. At 11 8/12 years, his height was 164.6 cm, close to his mid-parental target height of 165 cm. We report an additional nine patients with Klinefelter syndrome and GHD from the Pfizer International Growth Study (KIGS) database, none of whom had CPP. We conclude that the combination of GHD and CPP is very rare in Klinefelter syndrome and that CPP is unlikely to compromise final adult height.

Insulin receptor mutations cause extreme insulin resistance resulting in acanthosis nigricans and hyperandrogenism. We report a pre-menarchal adolescent female with normal weight, with severe acanthosis nigricans, acne, and hirsutism. Initial investigation revealed elevated fasting and post-prandial insulin and high testosterone and androstenedione levels. Her father had frequent complaints of hypoglycemia. Coding sequence and splice junction analysis of the INSR gene, in our patient and her father, revealed a heterozygous missense mutation in the β subunit of the insulin receptor (Arg1131Trp), resulting in receptor loss of function. Metformin therapy and carbohydrate control improved acanthosis and menarche ensued within 3 months. Our case highlights the importance of distinguishing insulin resistance commonly associated with obesity from monogenic defects. Although, there is no consensus on treatment of children with monogenic forms of insulin resistance due to its rarity, dietary and lifestyle modifications and insulin-sensitizing agents play a key role in management.